Metal Vapor Vacuum Arc Research Articles

Fast deposition of thick diamond-like carbon films by ion-beam technique

A diamond-like carbon film doped with TiC nanocrystallites (TiC–DLC) with a thickness of 35.8 μm was successfully prepared on a stainless steel substrate by employing a combination of metal vapor vacuum arc and filtered cathode vacuum arc techniques. A maximum deposition rate of 0.25 μm/min was achieved for TiC–DLC films. The structure and properties of the TiC–DLC films were systematically analyzed using different methods such as transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, X-ray diffraction, and friction and wear tests. The results indicated that typical a-C:H films containing nano-sized TiC grains were deposited which exhibit improved mechanical properties such as high cohesive strength, Vickers hardness, and capacity against high temperature. Parameter windows for C2H2 flow rate and solenoid current were also provided for the deposition of TiC–DLC films to meet the requirements for using the material for specific commercial applications.

Effects of the implantation of Sn ions in W; chemical state, crystal structure and hardness

Prior to the practical application of liquid metals as facing material for fusion reactor, the nature of the interaction layer between liquid metal and tungsten substrate should be studied deeply. In the present work, by means of ion implantation technique using a metal vapor vacuum arc source (MEVVA), Sn ions were injected into a W matrix and a W-Sn modified layer was prepared. The chemical state, crystal structure and nano-indentation hardness of the modified layer were investigated and characterized with the use of X-ray photoelectron spectroscopy (XPS), an X-ray diffractometer (XRD) and a nano-indentor. The results indicate that, after the injection of Sn ions into the W matrix, Sn atoms interacted intensively with W, leading to the generation of a large number of point defects (such as vacancies and self-interstitial atoms) and the decrease of average grain size from 16.7 to 11.9 nm. Additionally, chemical shifts appeared, i.e., the binding energy values of W 4f7/2, W 4f5/2, W 5p3/2 and W 4p1/2 in the modified layer was reduced by 0.3 eV, 0.3 eV, 0.4 eV, 1–1.4 eV, respectively. The binding energy values of Sn 3d5/2 and Sn 3d3/2 decreased, with a chemical shift of 0.6–0.7 eV and 0.1–0.3 eV, respectively. The nano-indentation hardness of the modified layer was enhanced; specifically, when the indentation depth was 26.3 nm, the hardness reached a peak value of 13.8 GPa. In the modified layer, the surface chemical states are quite complex, mainly including SnO, WO3, SnO2 and WC.

Improved cytocompatibility of Mg-1Ca alloy modified by Zn ion implantation and deposition

The Mg-1Ca alloy has been modified by Zn ion implantation and deposition (II&D) using metal vapor vacuum arc plasma source (MEVVA). The surface characteristics, corrosion behavior and cytocompatibility were investigated. The auger electron spectroscopy (AES) results showed that a uniform ZnO layer was formed on the surface of Mg-1Ca alloy. The electrochemical measurements revealed that the corrosion potential has been increased, and a comparable corrosion current density in the simulated body fluid (SBF) was obtained for the Zn-modified Mg-1Ca alloy. The indirect cell viability evaluation and direct cell culture results indicated that the cytocompatibility of MC3T3-E1 cells on the Mg-1Ca alloy was improved by the ZnO layer on the surface.

Fabrication of highly transparent Al-ion-implanted ZnO thin films by metal vapor vacuum arc method

In this study, we utilized the metal vapor vacuum arc technique to implant vaporized aluminum (Al) ions in zinc oxide (ZnO) thin films. By adjusting the ion implantation dose and operational parameters, the conductivity and optical properties of the ZnO thin film can be controlled. The electrical sheet resistance of Al-ion-implanted ZnO decreased from 3.02 × 107 to 3.03 × 104 Ω/sq, while the transparency of the film was mostly preserved (91.5% at a wavelength of 550 nm). The ZnO thin-film Young’s modulus significantly increased with increasing Al ion dose.

Molybdenum Concentration Depth Profile in Aluminum Implanted by Multi-charged Molybdenum Ions

In addition to the accelerating voltage of ions, ion charge state, ion sputtering, diffusion and phase change will all affect the concentration depth distribution. In order to distinguish the influence degree of the various factors, appropriate computational and experimental approaches must be put forward. Molybdenum ions from a metal vapor vacuum arc (MEVVA) ion source are implanted into aluminum to investigate the influence factors of the concentration depth profiles. The results of high voltage electron microscopy (HVEM) have showed that phase change are not induced by molybdenum ion implantation of an average current density of lower than 20μA/cm2. Rutherford backscattering spectroscopy (RBS) is used to investigate the Mo concentration depth profile in the Mo-implanted Al. RBS from Mo-implanted Al is converted to Mo concentration depth distribution considering the change of stopping cross section induced by high dose ion implantation. The measured concentration depth profile is compared with the calculation result of the TRIDYN program, in which sputtering and multi-charged state can both be considered dynamically. The deviation of the experiment and simulation results could be attributed to radiation enhanced diffusion or intense pulse beam current density implantation.

Effect of titanium ion implantation and deposition on hydrogenation behavior of Zr-1Nb alloy

In order to study the effect of titanium ion implantation and deposition on hydrogenation behavior of Zr–1Nb alloy, the samples were subjected to plasma immersion implantation and deposition (PIII&D) of titanium ions at the bias voltage of 0.5–1.5kV using a filtered metal vapor vacuum arc source. The crystalline structure, surface morphology and depth distributions of elements in the surface layer of the samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and glow-discharge optical emission spectroscopy (GD-OES), respectively. Hydrogen saturation was performed from hydrogen atmosphere at 673K temperature and 2atm. pressure. It was found that hydrogen absorption rate by Zr–1Nb alloy decreased after PIII&D. The modified layers contained a mixing zone of titanium and zirconium, which decreases with increasing bias voltage. Hydrogenation causes the formation of titanium hydrides and lattice distortions of α–Zr at the low bias voltage that does not occur at higher bias voltages. The hydrogenation behavior of modified zirconium alloy was discussed.

Accelerating degradation rate of pure iron by zinc ion implantation.

Pure iron has been considered as a promising candidate for biodegradable implant applications. However, a faster degradation rate of pure iron is needed to meet the clinical requirement. In this work, metal vapor vacuum arc technology was adopted to implant zinc ions into the surface of pure iron. Results showed that the implantation depth of zinc ions was about 60 nm. The degradation rate of pure iron was found to be accelerated after zinc ion implantation. The cytotoxicity tests revealed that the implanted zinc ions brought a slight increase on cytotoxicity of the tested cells. In terms of hemocompatibility, the hemolysis of zinc ion implanted pure iron was lower than 2%. However, zinc ions might induce more adhered and activated platelets on the surface of pure iron. Overall, zinc ion implantation can be a feasible way to accelerate the degradation rate of pure iron for biodegradable applications.

In vitro studies on silver implanted pure iron by metal vapor vacuum arc technique

Pure iron has been verified as a promising biodegradable metal for absorbable cardiovascular stent usage. However, the degradation rate of pure iron is too slow. To accelerate the degradation of the surface of pure iron, silver ions were implanted into pure iron by metal vapor vacuum arc (MEVVA) source at an extracted voltage of 40keV. The implanted influence was up to 2×1017ions/cm2. The composition and depth profiles, corrosion behavior and biocompatibility of Ag ion implanted pure iron were investigated. The implantation depths of Ag was around 60nm. The element Ag existed as Ag2O in the outermost layer, then gradually transited to metal atoms in zero valent state with depth increase. The implantation of Ag ions accelerated the corrosion rate of pure iron matrix, and exhibited much more uniform corrosion behavior. For cytotoxicity assessment, the implantation of Ag ions slightly decreased the viability of all kinds of cell lines used in these tests. The hemolysis rate of Ag ion implanted pure iron was lower than 2%, which was acceptable, whereas the platelet adhesion tests indicated the implantation of Ag ions might increase the risk of thrombosis.

이온빔을 이용한 STS304와 알루미나 브레이징 접합효과

Abstract Using a surface modification technique, ion beam assisted deposition (IBAD) of Ti thin film it becomes possible to prepare an active ceramic surface to braze Al 2 O 3 -STS304 with conventional Ag-Cu eutectic compositionfiller metal. Researches on bonding formations at interfaces of ceramic joints were mainly related on the developmentof filler metals to ceramic, the process parameters, and clarifications of reaction products. From the results, the reactive brazing is a very convenient technique compared to the conventional Mn-Mo method. However melting pointof reactive filler is still higher than that of Ag-Cu eutectic and it forms the brittle inter metallic compound. Recently several new approaches are introduced to overcome the main shortcomings of the reactive metal brazing in ceramic-metal, metal vapor vacuum arc ion source was introduced to implant the reactive element directly into the ceramics surface, and sputter deposition with sputter etching for the deposition of active material.

Surface modification of ferritic steels using MEVVA and duoplasmatron ion sources.

Metal Vapor Vacuum Arc (MEVVA) ion source (IS) is a unique tool for production of high intensity metal ion beam that can be used for material surface modification. From the other hand, the duoplasmatron ion source provides the high intensity gas ion beams. The MEVVA and duoplasmatron IS developed in Institute for Theoretical and Experimental Physics were used for the reactor steel surface modification experiments. Response of ferritic-martensitic steel specimens on titanium and nitrogen ions implantation and consequent vacuum annealing was investigated. Increase in microhardness of near surface region of irradiated specimens was observed. Local chemical analysis shows atom mixing and redistribution in the implanted layer followed with formation of ultrafine precipitates after annealing.

Local structure study of the Ni nanoparticles embedded in SiO2 by ion implantation

The extended x-ray absorption fine structure (EXAFS) and the Atomic force microscopy (AFM) have been used to study the local structural information of Ni nanoparticles implanted into glass. Three different concentrations of nickel nanoparticle samples were fabricated by metal vapor vacuum arc (MEVVA) source on amorphous silicon dioxide substrate at room temperature. With the increase of Ni ion implantation, the interatomic distance and the nearest neighbor coordination number of the nearest Ni–Ni bond and Ni–O bond of nickel nanoparticle presents certain regular change.

Surface properties of W-implanted TiN coatings post-treated by low temperature ion sulfurization

TiN coatings were implanted with W ions by metal vapor vacuum arc (MEVVA) source at dose of 9×1017ions/cm2, and then they were post-treated by low temperature ion sulfurization (LTIS) at 160°C. The W-implanted TiN samples were characterized before and after post-treatment of LTIS, using Scanning Electron Microscopy (SEM), Scanning Auger Microprobe (SAM), X-ray diffraction (XRD), and Nano Indenter System. Friction and wear properties were evaluated using a ball-on-disc tribometer under dry sliding in air. After post-treatment of LTIS, XRD results showed no diffraction peaks of tungsten sulfides on surfaces of W-implanted TiN coatings; W-implanted TiN coatings were sputtered by the sulfur plasma with about 36% reducing of W depth. Further, the nano-hardness decreased mainly due to the amount decreasing of Ti2N and the formation of more metal oxides on surfaces of W-implanted TiN coatings after LTIS. As a result, LTIS treatment could not well improve tribological properties of W-implanted TiN coatings.

Influence of biocompatible metal ions (Ag, Fe, Y) on the surface chemistry, corrosion behavior and cytocompatibility of Mg–1Ca alloy treated with MEVVA

Mg–1Ca samples were implanted with biocompatible alloy ions Ag, Fe and Y respectively with a dose of 2×1017ionscm−2 by metal vapor vacuum arc technique (MEVVA). The surface morphologies and surface chemistry were investigated by SEM, AES and XPS. Surface changes were observed after all three kinds of elemental ion implantation. The results revealed that the modified layer was composed of two sublayers, including an outer oxidized layer with mixture of oxides and an inner implanted layer, after Ag and Fe ion implantation. Y ion implantation induced an Mg/Ca-deficient outer oxidized layer and the distribution of Y along with depth was more homogeneous. Both electrochemical test and immersion test revealed accelerated corrosion rate of Ag-implanted Mg–1Ca and Fe-implanted Mg–1Ca, whereas Y ion implantation showed a short period of protection since enhanced corrosion resistance was obtained by electrochemical test, but accelerated corrosion rate was found by long period immersion test. Indirect cytotoxicity assay indicated good cytocompatibility of Y-implanted Mg–1Ca. Moreover, the corresponding corrosion mechanisms involving implanting ions into magnesium alloys were proposed, which might provide guidance for further application of plasma ion implantation to biodegradable Mg alloys.

Synthesis of Ag ion-implanted TiO2 thin films for antibacterial application and photocatalytic performance

TiO2 thin films were deposited by spin coating method. Silver ions were implanted into the films using a Metal Vapor Vacuum Arc implanter. The antibacterial ability of implanted films was tested using Escherichia coli removal under fluorescent irradiation and in the dark. The concentration of E. coli was evaluated by plating technique. The photocatalytic efficiency of the implanted films was studied by degradation of methyl orange under fluorescent illumination. The surface free energy of the implanted TiO2 films was calculated by contact angle testing. Vitamin C was used as radical scavengers to explore the antibacterial mechanism of the films. The results supported the model that both generation of reactive oxygen species and release of silver ions played critical roles in the toxic effect of implanted films against E. coli. XPS experimental results demonstrated that a portion of the Ag(Ag3+) ions were doped into the crystalline lattice of TiO2. As demonstrated by density functional theory calculations, the impurity energy level of subtitutional Ag was responsible for enhanced absorption of visible light. Ag ion-implanted TiO2 films with excellent antibacterial efficiency against bacteria and decomposed ability against organic pollutants could be potent bactericidal surface in moist environment.

Influence of Surface Nanocrystallization on Ti Ion Implantation of Pure Iron

In order to increase the depth or concentration of Ti ion implantation of pure iron, the surface mechanical attrition treatment (SMAT), which can fabricate a nanometer-grained surface layer without porosity and contamination in a pure iron plate, was used before ion implantation. Ti ion was implanted into the SMA treated sample and coarse-grained counterpart by using a metal vapor vacuum arc source implanter. The changing of depth and concentration of Ti was studied in a function of implantation time. By optical microscopy, transmission electron microscopy and X-ray diffraction, the grain size of the nano structured surface was studied. Micro-hardness, friction and wear behavior of nano surface layers were studied. By energy dispersive X-ray spectroscopy and Auger electron spectroscopy, the chemical composition and concentration of Ti ion in the surface implantation layer were studied. Experimental results showed that the concentration of Ti increased dramatically compared with untreated coarse-grained samples, which is attributed to the existence of higher density of defects (supersaturated vacancies, dislocations, non-equilibrium grain boundaries etc.) and compression stress field in the SMA treated nanocrystallined surface layer. The interaction between the defects and the implanted solute atoms leads to the increment of solid solubility. But the implantation depth showed inconspicuous change. It is shown that the ion range is just relevant to the energy and mass of the ion, dose of injection, the mass and density of target material.

Enhancement and quenching of photoluminescence from Au nanoparticles and CdTe quantum dot composite system

New composite systems consisting of Au nanoparticles (NPs) and CdTe quantum dots (QDs) are fabricated by spin coating chemically synthesizing CdTe QDs on silica substrates which have already been implanted by Ag ions through using a metal vapor vacuum arc (MEVVA) ion source implanter. By thermally annealing the Au ions implanted silica substrates, the growth and redistribution of Au NPs can be controlled, the influence of localized surface plasmon (LSP) of Au NPs on the photoluminescence (PL) of CdTe QDs is well studied. The optical properties, surface morphologies, microstructures, and light emission properties of the Au-ion implanted samples are investigated by using optical absorption spectroscopy, atomic force microscopy, transmission electron microscopy and PL spectra measurements. PL spectra show that the PL intensities from Au NPs and CdTe QDs composite systems can be enhanced or quenched compared with those of CdTe QDs directly spin coated on bare silica substrate. The underlying interaction processes between Au NPs and CdTe QDs are discussed in depth, and the new mechanisms for the PL enhancement and quenching in the Au-CdTe coupled systems are put forward. These results provide a good reference for the future designing of optoelectronic devices with improved luminescence efficiency by LSP of metal NPs.

Surface characteristics and corrosion resistance of biodegradable magnesium alloy ZK60 modified by Fe ion implantation and deposition

The ZK60 magnesium alloy has been modified by Fe ion implantation and deposition with a metal vapor vacuum arc plasma source. The surface morphology, phase constituent and elemental distribution are determined by scanning electron microscopy, transmission electron microscopy, X-ray diffractometer and Auger electron spectroscopy. The results show that Fe thin film is deposited on ZK60 alloy and the corresponding thickness increases from 2.73μm to 6.36μm with increasing deposition time. A transition layer mainly composed of Mg, Fe and O elements is formed between Fe thin film and ZK60 substrate. The potentiodynamic polarization tests reveal that a high corrosion potential and a low corrosion current density are detected for the Fe deposited ZK60 alloy, indicating the improvement of corrosion resistance. The tensile deformation test indicates that the Fe deposited film on the ZK60 substrate can sustain 1% tensile strain without any cracks.

Room temperature ferromagnetism studies in Fe ion implanted indium oxide films

Diluted magnetic semiconductor based on indium oxide has been prepared by Fe ion implantation. Pure In2O3 films are Fe ion implanted by metal vapor vacuum arc source with doses of 5×1015, 1×1016 and 4×1016cm−2, respectively. The implanted samples are separately annealed in vacuum and O2 subsequently. The structure of In2O3 films is characterized by X-ray diffraction and high resolution transmission electron microscopy. X-ray photoelectron spectroscopy measurements are applied to research the electronic state of the implanted ions. Superconducting quantum interference device measurements at room temperature disclose that both pure and Fe implanted In2O3 films are ferromagnetic, and the ferromagnetism is enhanced with the increase of implantation dose. The ferromagnetic mechanism is discussed. The bound magnetic polarons formed by Fe ion implantation and the oxygen vacancy may be responsible for the observed results.

Nanoindentation characterization of tetragonal zirconia polycrystalline implanted by titanium ions with MEVVA sources

The applicability and the reliability of the traditional power-law proposed by Oliver and Pharr in describing the nanoindentation unloading behavior of the ion-implanted samples were examined in this paper. Nanoindentation tests were conducted on a tetragonal zirconia polycrystalline (TZP) ceramic implanted by titanium ions with metal vapor vacuum-arc (MEVVA) sources. Both the power law (a paraboloid punch approximation) and the quadratic polynomial (conical indenter approximation) were employed to analyze the unloading portions of the resultant load-displacement curve. It was found that, when the examined contact depth is smaller then the thickness of the ion-implanted layer, the determined power law exponent, m, is much larger than 1.5, the theoretical value for a paraboloid punch. This phenomenon may be attributed mainly to the effect of the residual surface stresses associated with the ion implantation. The hardness and Young's modulus of the ion-implanted sample were found to exhibit a graded distribution and have maxima when the contact depth is comparable to the average projected range of the implanted ions.

Nonlinear optical refraction of Al2O3 single crystal doping with nickel nanoparticles measured by the Kerr-lens autocorrelation technique

The nonlinear refraction of a nickel doped α-Al2O3 single crystal was measured with a 800 nm pulse using the Kerr-lens autocorrelation technique. The sample was fabricated by ion implantation using a metal vapor vacuum arc ion source. The value of the nonlinear refractive index, n2, of the sample was determined to be 7.9 × 10−16 cm2 W−1. The mechanisms of nonlinear refraction of the bulk material and the nanoparticles have been discussed through the UV–vis spectrum and supercontinuum spectra.